APA Dictionary of Psychology

adj. a term coined by British writer Aldous Huxley (1894–1964) to describe the effect of mind-altering drugs, such as LSD (from Greek phanein, “to reveal,” and thymos, “mind, soul”). He first used the term in a letter (1956) to his friend Humphry Osmond (1917–2004), who counterproposed the term psychedelic, which has the same etymological sense of “mind-revealing.” See also hallucinogen.